Two bellwether states in the midterm Senate scramble feature races that are statistically dead even, with 72 hours to go before the polls open.

Iowa, where GOP state senator Joni Ernst is battling Democrat Rep. Bruce Braley, and North Carolina, where incumbent Senator Kay Hagan is facing off against NC Speaker of the House Thom Tillis, are both too close to call, and desperately needed by both parties to swing control of the upper chamber their way.

Politico:

New CNN/ORC International polls released late Friday show the closely watched Senate races in Iowa and North Carolina in virtual dead heats.

Iowa Republican Joni Ernst leads Democrat Bruce Braley by 2 points among likely voters, 49 percent to 47 percent. In North Carolina, Democratic Sen. Kay Hagan leads Republican Thom Tillis by 2 points among likely voters, 48 percent to 46 percent.

Barack Obama has seen a slight uptick in his approval rating since last month in both CNN polls. The president’s approval is 45 percent in North Carolina and 42 percent in Iowa. It was 38 percent and 39 percent respectively, in surveys last month.

Tillis, the Speaker of the North Carolina state House, has taken a beating in negative ads all year. He’s underwater going into the final weekend, viewed favorably by 43 percent and unfavorably by 50 percent. Just one month ago, he was viewed favorably by 47 percent and unfavorably by 40 percent.

Hagan is viewed favorably by 49 percent and unfavorably by 48 percent.

In Iowa, both candidates are viewed favorably by 49 percent and unfavorably by 47 percent. Early last month, Braley was at 48 percent favorable/43 percent unfavorable, and Ernst was at 47 percent favorable/47 percent unfavorable.

The voter screens show how much is at stake in Democratic efforts to expand the electorate with ambitious field programs. Among the larger samples of registered voters, Braley and Hagan each lead by 6 points.

In both races, 90 percent of likely voters said they’ve made up their mind.

That's actually a lot of undecideds at this late date, although a substantial number of them may make up their minds over the weekend.

Other recent polls confirm the CNN survey: Hagan and Ernst are both slightly ahead.  What should both worry and excite the GOP is that a substantial number of these toss-up races – ten of them by Nate Silver's count – will probably break for one party or the other.  And with the news that the GOP has built up a 100,000-vote lead in Colorado early voting, the signs are present for a genuine GOP wave to materialize on Tuesday.

With the good news starting to roll over the weekend, it is important to remember the words of that great philosopher, Han Solo:

"Great, kid!  Don't get cocky."